Dallas Cowboys defensive end Randy Gregory, who played in his first regular-season game since 2016 on Sunday, suffered a substance abuse relapse last month that the NFL could rule on as early as this week, league sources told ESPN.

Sources in Dallas thought the league would decide whether to discipline Gregory last week, before Sunday's regular-season opener against the Carolina Panthers, but the league still is studying the case and factoring in the steps that Gregory has taken over the past month since his setback.

Gregory suffered a concussion in the second quarter Sunday and didn't return to the game.

More and more, in one of the intriguing and quiet trends around the league, the NFL has become more tolerant when a player violates the drug policy. It has softened its stance on drug policy perpetrators. According to league sources, there have been examples this offseason of a player having a disputed test, with the league emphasizing treatment and support rather than discipline, which was one of the NFL Players Association's goals when the policy was reconfigured in 2014.

Within the past year, the NFL has recognized that addiction is best treated in ways other than suspending players, sources said. Gregory is the latest example, though he still faces a key ruling that could come as early as this week.

Prior to Sunday's action, Gregory had missed 30 of the previous 32 regular-season games, including the entire 2017 season, for multiple violations of the league's substance abuse policy. He was reinstated by the league in July after meeting with commissioner Roger Goodell.